package com.hmdp.utils;

import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;

import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;

//用Redis实现全局ID自增

@Component
public class RedisIdWorker {

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    //开始时间戳
    private static final long BEGIN_TIMESTAMP = 1735689600;

    //序列号位数
    private static final int COUNT_BITS = 32;

    public long nextId(String keyPrefix){

        //1.生成时间戳
        LocalDateTime now = LocalDateTime.now();
        long nowSecond = now.toEpochSecond(ZoneOffset.UTC);
        long timeStamp = nowSecond - BEGIN_TIMESTAMP;

        //2.生成序列号
        //2.1先获取当前日期，精确到天，目的：为了使key值在每一天都不相同
        String date = now.format(DateTimeFormatter.ofPattern("yyyy-MM-dd"));
        //2.2实现序列号自增长
        long count = stringRedisTemplate.opsForValue().increment("icr" + keyPrefix + ":" + date);

        //3.拼接并返回
        return timeStamp << COUNT_BITS | count;
    }

    //获取2022年1月1日0时0分0秒时间的秒数作为初始时间
    public static void main(String[] args) {
        LocalDateTime time = LocalDateTime.of(2025, 1, 1, 0, 0, 0);
        long epochSecond = time.toEpochSecond(ZoneOffset.UTC);
        System.out.println("second=" + epochSecond);

    }
}
